Device for rectifying the involute tooth-profile of gear grinding disks



May 15, 1945. A. AEPPLI 2,376,109 DEVICE FOR RECTIFYING THE INVOLUTETOOTH-PROFILE 0F GEAR GRINDING DISCS Filed Nov. 12. 1945 Patented May15, 1945 r nnvion' 'ron 'REU'IIFYING THE INVOLUTE or GEAR; cmnnm u iTOOTH-PROFILE T ,DISKS AlberthepplL. zurich, Switzerland, assignor to vMaag-Zahnrader und-Maschinen Aktiengesellscha'ft', Zurich, SwitzerlandApplication November 12, 1943, Serial No. 510328 .In Germany June 11,1942 ,vcla'im (01. 125-11) a Thi'sinvention relates todevices forrectifying the involuble tooth-profile of gear grinding disks. Indevices of this kind hitherto known inwhich the involuble tooth-profileto be formed on the grinding disk is produced. on the principle ofrelative rolling motion between elements, the

rolling disk must always be displaced laterally from the plane passingthrough the axis of the grinding disk and the point of the diamond in anamount approximating the radial length of thegrinding disk; for thepurpose of giving. free the space required for the rolling. elements toperform their rolling movements. This leadsto an: arrangement in whichthe diamond. is fastened tothe end of a long armwherebyv the devicebecomes unstable and the exactness. of the involute form produced isimpaired.

The present invention has for its object to arrange the rolling diskdirectly underneath the grinding disk with a view to dispensing with thearm forsupportingthe diamond turning tool and providing for the-deviceto become rigid and the involute curve produced to be true to"form-.j

A,-,further object of the presentinvention consists in that with asingle rolling arc involute curves for gears with difierent pitchcircles can be produced.

A still further object consists in'pro'ducin'g with thedevice; in asimple mannena tooth-outline diverting somewhat from the true involutecurve, that is, the tooth-profile of the disk is intended to be given,for example, such a' form that the hitherto often requiredadditional'rounding' off of the taco or the rooth'of the teeth,respectively, can be dispensedwith- The first named object-is carriedinto effect in thata" carrier is arranged for rocking movement about theaxis of a rolling disk on which carrier on one side of said axis ofrotation a rectilinear rollinginemberfisguided and is secured to saiddisk by means'ot rollingstrips, the diamond-being mounted on th'eopposite side on a plungergzthe guide means of which on the carrierextends parallel with the rectilinear rolling member,-and the latter andthe plunger of therdiamondturnin'g toolbeingoperatively'connected witheach other by means ofja leverage.

The aforesaid second object ;is realised-in that for the plunger of thediamond turning tool a guideway is arranged on a sliding member which isdisplaceably guidedon the rockablecarrierat is the fact that :inconsequenceof. said. displacing movement the ratio of arm lengths ofsaid lever" I right angles to the rolling member. Proof of this age fromthe axis of rotation of the latter to the point 'of'contact of therolling member and from said rotation axis'to the point of contact 0:1the diamond turning tool is varied.- This ratio is however like thatexisting between the diameter of the rolling disk 'and'that of the pitchcircle of thetooth system'to be ground. The diameter of this pitchcircle can jthusbe varied while the roll ing disk used can remainunchanged. Final1y,'the third mentioned'object can be'carried out inthat one of the "ends of the lever of the leverage is diverted from therectilinear form by which means a form jof-tooth-profile is obtained'which deviates from the involute curve. I

In the accompanyingdrawing anfold form of rectifying deviceisillustrated together with an exem'plificatiori' ofthe 'sjulojei zt ofthe present invention inclusive of detail modifications of the latter. vr

"Fig. 1 shows a side elevation of a known rectifying device; I 1 Fig. 2shows a corresponding front elevation; Fig. 3 shows a front elevation ofa preferred form of the present invention; r t :Fig. 4 shows acorresponding side elevation;

Fig. ,5 is a section on the line V--V in Fig 3; v Fig. 6 shows amodified detail of Fig. 3;

Fig, 7 is a section on the line VIIVII in Fig. 6; Fig. 8 is a diagramillustrating differentrelative movements, and

Fig. 9 is a schematic view representing a modified formofthe'deviceaccording to the present invention adapted'for'working withscrew wheel grinding disks. In the old device a turning mechanismoperating on the principle of relative rolling motion between two partsisused' for rectifying the involute tooth-profile of the grinding diskN, the stationary'rolling disk W of which mechanism extends in a planethe distance of which from the middle plane E-E of the grinding diskamounts to the radial length of said disk at'least; On this rolling diskW rolls a rule G which can be connected with the disk W by means ofrolling strips. To this rule is connected an arm A which liestransversely to .the latter and carries the diamond turning tool D. Dueto the fact that the thrust in the first In the form of this inventionshown in Fig. 3 this result has been obtained by securing a supportingstructure 20 to the bed of the machine, in which this disk to berectified by being turned 01f is mounted underneath the profilegenerating disk N, which structure includes a shaft bearing 2! and arolling segment 2 coaxially connected with the supporting structure.bearing 2| rests a journal pin l which is rotatable in said bearing andsecured to the carrier 3. The carrier 3 is provided with two perforatedears 4 in which a rectilinear rolling member or rule 5 is mounted freefrom play. This rule is connected wit-h the rolling segment 2 by meansof rolling strips 6 and I.

In addition, the carrier 3 is provided With a slideway 9 which extendsat right angles .to the rule 5 and on which a slide ,8 is displaceablyguided and adapted to be secured in position of adjustment. The slide 8in turn carries a slide way which extends transversely of itslongitudinal direction and serves for the reception of a plunger II. Onthe latter the diamond turning tool I2 is adjustably fastened. Foreffecting this fastening on the plunger l l a turntable 22 is arrangedrelative to which a holder 24- for the diamond I2 can be shifted and canbe fixed thereon in position of adjustment by means of a spindle and aknurled button 23.

Further to the carrier 3 a mounting support 14 is screwed which receivesan axle pin l3 extending paral1e1 with the pin I. On this axle pin aroller 25 and guide pieces l6 are mounted as well as springs it whichmaintain a rail IS in bearing engagement with the roller 25 by means ofa cross piece. This rail is positioned between the guide pieces IS. Theconnecting line between the centers I and I3 extends parallel to therule 5.

The rail l5 forms a two-armed lever with which the plunger ll of thediamond turning tool and the rule 5 are articulated. Such a pivot jointis shown in plan in Fig. 6 on a larger scale. similar to that existingbetween the carrier 3 and the rail l5 and formed by a roller 25 which isforced into bearing engagement with the rule-- by means of springs l8and a cross piece H. The

rollers 25 are mounted on the parts I I and 5 respectively, in suchmanner, that a line extending tangentially to the rolling segment 2 inparallelism to the rule 5 passes through the axis of the roller on therule 5, and that a straight line extending parallel to said tangent andpassing through the diamond turning tool 12 intersects the center of theroller 25 on the slide l I, if the projection represented by Fig. 3 istaken into consideration. As the carrier 3 is pivo-tally displacedrelative to'the support the point of the diamond describes an involutecurve. It will be seen that the rectifying device described is arrangeddirectly underneath the grinding disk so that the supporting arm A shownin Figs. 1 and 2 is dispensed with. Therefore, the described arrangementprovides for guiding the diamond turning tool much more rigidly andprecisely.

In Fig. 8 the relative movements of parts are represented. The characterdo denotes the diameter of the pitch circle for which the in-,

volute curve is to be evolved. D0 refers to the diameter of the rollingsegment 2 in Fig. 3 by means of which the involute is to be effected.The character C indicates the fulcrum I3 of the lever l5. The tangent tothe root circle of diameter do represents the joining line passingthrough the point of the diamond l2 and the It is In the point ofcontact of the lever [5 with the plunger I l The tangent to the rollingcircle of diameter Do corresponds to the contacting line of the guiderule 5 passing through the point of contact between the lever l5 andsaid rule and extends tangentially to the rolling segment 2.

If, with the center assumed to remain in stationary position, the pitchcircle do (Fig. 8) is to roll on the straight line a-b this line ab mustbe displaced relative to the center in the direction of arrow F, onrotation of the pitch circle through an angle a, for a stretch ap equalto an arc length aa'. If ap equals a-a' point p coincides with point aat the end of the rotational displacement for the angular range a.

From Fig. 8 it is evident that on rolling movement for the angular rangeon the rolling circle of diameter Do a length of rolling equalling thearc length AA' is obtained. If the length AP of the straight line equalsA-A' the points A and P coincide on the termination of the rotationmovement.

Therefore, as

it follows that on the circle of diameter D0 rolling on the straightline AB the pitch circle of diameter do performs a rolling motion on thestraight line a-b. Therefore, it is possible to evolve the involute on apitch circle of any desired diameter of pitch circle in using theleverage described, as long as the relation C b Do C'-B d0 exists.

With the aid of such rectifying devices toothprofiles diverting from theinvolute, having, for example, the tooth faces rounded off can beproduced in a simple manner, for example, by giving to the lever a formwhich is diverted from the rectilinear contour, as indicated by a dottedline in Fig. 8.

Such a device can be carried into eficct by varying the construction,for example in a manner as shown in Fig. 6. The lever end portionsituated on the side of the rolling segment 2 in Fig. 3 is thus providedwith an exchangeable piece I5 which is accordingly curved. By this meansthe result is obtained that during the end portion of the rolling motionthe displacement of the diamond plunger is somewhat increased, so as tobecome greater than required for producing the true involute form.Consequently the tooth-profile turned onto the disk is bulged outward.

The desired result can, however, be obtained also in that, for example,contacting en agement between the rolling rule 5 and the lever I5 iseffected with the aid of a cam which is controlled by a lever arm andcomes to bear either on the carrier 3 or the lever l5 when the rollingmotion has been carried on to a certain extent. Thereby, a rotatingmovement is initiated by effect of which the diamond is displaced atvariance from the displacement imparted to it through the correctleverage.

In applying the last named procedure, the varying of the ratioofleverage cannot be effected to any desired extent with the same easeas resulting from the use of a curved lever end portion.

rolling disk, coordinated withthe axis of rolling movement, andacooperative rectilinear 11 n eitectmg the tooth-profiles on thegrinding 'diskthe rectifying device is convenientlyclamped in positionbetween the centering points instead 1 of tnus'clampingly holding inplace the-sear to ground "By-rocking the carrier- 3 to and fro theihvoluteis evolved and the disk turned off.

--In pro'ducin'g's'pur as well as screw'gearsalways theinvoluteappropriate "for the gear end face is carriedinto efiect'for'the reason that the rolling "motion can be cam-red outbnly in the planeof-the rolling disk which extends plan'e'S"(-Flg.9)." I v 1337 means ofthe device describ ed also such grinding disks can be "rectified whichare inparallel to the front tended for grinding screw'gear's. InsO'dOing, apart from=the rolling motionwhich in thisin- I 'stant isefiected by the diamond plunger, the rollmember, means for effectingrelative rolling movement between said disk andsaid member "about saidaxis, a c'arrier coaxially arranged with said diskfor-pivoting-movementabout said axisfslide guides ior displaceably' guiding said rectilinearrolling member arranged on said carrier on one side of said axis, aturning-tool carrier plunger disposed on said carrier on the other sideofsaid axis, means for guiding said plungerv parallel with said rollingmember, a

-levera'ge including a two-armed lever. operatively. connecting said Imember with said plunger, a fulcrum arranged for said lever on saidcarrier so that the joining line intersecting ing plane-mustbe graduallydisplaced longitudinallyof a helix in a manner known per se. Theturning-oft of the disk must, therefore, be effected feach other-atminute spacings-apart with a view to obtaining the true involute form;,In connection therewith the pointof the diamond must be adjusted {hirea position substant ally at right angles totheplaile of thegrindingdisk, For this,

pur ose, in-"rectifyi'ng devices for screw'wheels the" diamond holder isarranged on the diamond plunger-so that it can be turned relativelythereto and clamped inposition thereon. I

-In -.-th'epreceding' description it is stated that "said fulcrum' andsaid axis extends parallel with said rolling membergand an articulationbetween one arm of said lever and said plunger, said leverage arrangedto provide a ratio of theoretical lever armlen'gths between saidfulcrum'and the pointof rolling contact of said member and thefrollingoperation is carried out'by'mean's of a rolling rule through theintermediary'of rolling strips; It is, however.'-a lsofeasible to use a.

toothed sector "cooperating with a racku I v Iclaim: Y 1-. In a devicefor rectifying involute-tooth profiles on-grindingdisk-S for geargrinding machines,

a roll'irigdisk, coordinated 'with'the ax s of'rollr ing movement, and acooperative rectilinear rolling member, means foreffecting relativerolling movement between said disk and said member about-swaaxis, acarrier coaxially arranged with said'disk" for pivoting movement aboutsaid axis, I slid'eguides for displaceably guiding saidrectilinear-selling member arranged on said. carr er on onesidegof saidaxis, a turning tool carrier plunger disposedon said carrier on theother side "of said-axis;'meansfor guiding said plunger parallel with:said rolling member, and a leverage'opbetween said fulcrum and saidarticulation equalling the ratio of the diameter of saidrolling disk andsaidpitch circle diameter. r 4, a device for rectifying involute-toothprofiles ongrinding disks for gear grinding machines,for grindingworkpieces constituted by a gear havinga pitch circle, in combination, a

rolling disk coordinated with the axis of rolling movement, the diameterof said 1 disk being greater than that ofsaid pitch' circle-a -recti"linear rolling membencooperatmg with said disc, means for efie'ctingrelative rolling movement between said disk and said member about saidaxis, a carrier coaxially arranged with said disk for pivoting movementaboutlsaid axis,

sli'd guides for displaceablyiguiding said- -rectilinear rolling memberarranged on said carrier on one side of said'a'xis, atu'rning toolcarrier plunger disposed on said carrier on the other side of said axis,means -forguiding said plunger parallel' with said rolling member, a

I leverageincluding a two-armed lever operatively 'e'rativelyconnectingsaid; member with said plunger disposed on said. carrier on the otherside,

of said axis, means for guidin said plunger parallel with said rollingmember, a leverage including a two-armed lever operatively connect ngsaid member with said plunger, and a fulcrum arranged for said leveronsaid carrier so that the joining line intersecting said fulcrum and saidaxis extends parallel with said rolling member.v

3. In a device for rectifying involute-tooth profiles on griding disksfor gear grindingmachines, for grinding work pieces constituted by 1 agear having a pitch circle, in combination, a

connecting saidjfmember with said 1 plunger,- a fulcrum arranged forsaid lever on said carrier so that the joining line intersecting-saidfulcrum 'and 'said axisexten'ds parallelfwith said rolling member, andarticulations between said lever arms and said plunger and said 1 memberf' ;y leverage arranged to provide "-a'ratio of theoretical leverarm'lengths between said fulcrumand the point of rolling contact of saidmember and between said plunger articulation equalling, the ratio of thediameter of said rolling disk and said pitch circle diameter.

'5. In a device for rectifying iinvolute-tooth profiles on grindingdisks for gear grinding ma:-

chines, for grinding work pieces constituted by a gear having a pitchcircle, in combination, a rolling disk coordinated with the axis ofrolling movement, the diameter of said disk being greater than that ofsaid pitch circle, a rectilinear, rolling member cooperating with said Pdisk, means for efiecting relative rolling movement between said discand said member about said axis, a carrier coaxially arranged with saiddisc for pivoting movement about said axis, slide guidesior'displaceably guiding said rectilinear rolling member arranged onsaid carrier on one side of said axis, a turning tool carrier plungerdisposed on said carrier on the other side of I said axis, means forguiding said plunger parallel with said rolling member, as1ide:'carrying said plunger guide means displaceably arranged on saidcarrier in a direction at right angles to said rectilinear rollingmember, a levera'geincluding a two-armed lever operatively connectingsaid member with said plunger, and a fulcrum arranged for said lever onsaid carrier so that the joining line intersecting said fulcrum and saidaxis extends parallel with said rolling member.

6. In a device for rectifying involute-tooth profiles on griding disksfor gear grinding machines, for grinding work pieces constituted by.

a gear having a pitch circle, in combination, a rolling disk coordinatedwith the axis of rolling movement, the diameter of said disc beinggreater than that of said pitch circle, a rectilinear rolling membercooperating with said disk, means for effecting relative rollingmovement between said disk and said member about said axis, a carriercoaxially arranged with said disk for pivoting movement about said axis,slide guides for displaceably guiding said rectilinear rolling memberarranged on said carrier on one side of said axis, a turning toolcarrier plunger disposed on said carrier on the other side of said axis,means for guiding said plunger parallel with said rolling member, meansfor altering said parallel movement of said plunger for diverting saidtool from its course for producing the correct involute form at certainpoints of the tooth-profile, a leverage including a twoarmed leveroperatively connecting said member with said plunger, and a fulcrumarranged for said lever on said carrier so that the joining lineintersecting said fulcrum and said axis extends parallel with saidrolling member.

7. In a device for rectifying involute-tooth profiles on grinding disksfor gear grinding machines, for grinding work pieces constituted by agear having a pitch circle, in combination, a rolling disk coordinatedwith the axis of rolling movement, the diameter of said disk beinggreater than that of said pitch circle, a rectilinear rolling membercooperating with said disk, means for effecting relative rollingmovement between said disk and said member about said axis, a carriercoaxiallyarranged with said disk for pivoting movement about said axis,slide guides for displaceably guiding said rectilinear rolling memberarranged on said carrier on one side of said axis, a turning toolcarrier plunger disposed on said carrier on the other side of said axis,means for guiding said plunger parallel with said rolling member, aleverage including a two-armed lever operatively connecting said memberwith said plunger, said lever having an end portion diverting from itsrectilinear outline for diverting said tool from its course forproducing the correct involute form, and a fulcrum arranged for saidlever on said carrier so that the joining line intersecting said fulcrumand said axis extends parallel with said rolling member.

8L In a device for rectifying involute-tooth profiles on grinding disksfor gear grinding machines, for grinding work pieces constituted by agear having a pitch circle, in combination, a rolling disk coordinatedwith the axis of rolling movement, the diameter of said disk beinggreater than that of said pitch circle, a rectilinear rolling membercooperating with said disk, means for effecting relative rollingmovement between said disk and said member about said axis, a carriercoaxially arranged with said disk-for pivoting movement about said axis,slide guides for displaceably guiding said rectilinear rolling memberarranged on said carrier on one side of said axis, a turning toolcarrier plunger disposed on said carrier on the other side of said axis,means for guiding said plunger parallel with said rollingmember, aleverage including a two-armed lever operatively connecting said memberwitn said plunger, a separate piece exchangeably connected to an endportion of said lever and provided with an outline diverting from therec tilinear outline of said lever for diverting said tool from itscourse for producing the correct involute form, and a fulcrum arrangedfor said lever on said carrier so that the joining line intersectingsaid fulcrum and said axis extends parallel with said rolling member. i

9. In a device for rectifying involute-tooth profiles on grinding disksfor gear grinding machines, a rolling disk, coordinatedwith the axis ofrolling movement, and a cooperative rectilinear rolling member, meansfor efiecting relative rolling movement between said disk and saidmember about said axis, a carrier coaxially ar ranged with said disk forpivoting movement r about said axis, slide guides for displaceablyguiding said rectilinear rolling member arranged on said carrier on oneside of said axis, a diamond turning tool carrier plunger disposed onsaid car-- rier'on the other side of said axis, means for guiding saidplunger parallel with said rolling member, and a leverage operativelyconnecting said member with said plunger.

ALBERT AEPPLI.

